CAMARILLO, Calif. (CNN) -- Gas prices rose nearly 6 cents per gallon of self-serve regular during the past two weeks, to $2.61, a survey said Sunday.
That's less than a third of the 20-cent-per-gallon increase that occurred during the prior two weeks, and may indicate prices are leveling off, said Trilby Lundberg, publisher of the "Lundberg Survey," which tallies prices at about 5,000 gas stations every two or three weeks.
Sunday's results were based on surveys taken March 23 and March 9.
Lundberg credited the 5.57-cent increase on slightly higher crude oil prices and continued lower activity at refineries as they undertake seasonal repairs.
Demand for gasoline remains strong, in part due to the additional driving that resulted from this year's early start of Daylight Saving Time, she said.
"The runup will probably come to an end very soon," she said, citing the continuing repairs to refineries. "Several projects are already completed," she said.
In some cities, prices have already begun to fall, Lundberg added.
The lowest prices were in St. Louis, where a gallon of self-serve regular averaged $2.34, and where taxes are also low, she said.
San Francisco drivers paid the most, at an average of $3.19 per gallon.
Here are average prices in some other cities:
-- Dallas: $2.44
-- Atlanta: $2.46
-- Detroit: $2.51
-- Denver: $2.53
-- Philadelphia: $2.65
-- Hartford: $2.72
-- Portland, Ore.: $2.83
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Special Report: Gas Crunch 2007 
